The relative decrease change. Definition:
The relative decrease change is the difference in an indicator over two periods in time, v1 - v2, relative to the value of the indicator in the earlier period, v1.
- Where:
- v1 - is called the reference value (original, initial number);
- v2 - is called the new value (the end value).
- In our case: v1 = 225, v2 = 208.9.
The relative decrease change. Formula:
The relative decrease change =
The actual change / |v1|
(v1 - v2) / |v1| =
- Legend:
- v1 - the original number
- |v1| - the positive value of v1, |v1| >= 0. By example: |10| = 10; |-10| = 10.
- v2 - the new value
- The actual change = v1 - v2
- / - the fraction bar (division)
Why do we use |v1| in the formula instead of v1?
- Let's see what happens if we use v1 instead of |v1|:
- Choose a random negative number as the initial value: - 82.
- Choose a random positive number for the end value: 83.
Formula and calculation:
(v1 - v2) / v1 =
(- 82 - 83) / - 82 =
-165 / - 82 ≈
2.012195121951 ≈
2.01
Although the absolute difference is negative: -165, the relative decrease change is positive: 2.01. By using |v1| instead of v1, the error is corrected.
The relative percent decrease change. Detailed calculations below
By multiplying a number by the fraction 100/100,
we change only the form of the result, not the result.
- 100/100 = 100% = 100 ÷ 100 = 1.
- n × 100/100 = (n × 100)/100 = (n × 100)%, any number.
The relative percent decrease change. Formula:
The relative percent decrease change =
The relative decrease change × 100/100 =
(The relative decrease change × 100)/100 =
(The relative decrease change × 100)%
Calculate the relative percent decrease change:
(225 - 208.9)/|225| =
16.1/225 =
16.1 ÷ 225 =
16.1 ÷ 225 × 100/100 =
(16.1 × 100 ÷ 225)/100 =
(1,610 ÷ 225)/100 ≈
7.155555555556/100 =
7.155555555556% ≈
7.16%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 225 to the final, end value 208.9:
Rounded off to max. 12 decimal places ≈ 7.155555555556%
Rounded off to max. 2 decimal places ≈ 7.16%
The absolute (actual) difference
225 - 208.9 = 16.1
By what percentage has 225 decreased?
Answer: By ≈ 7.16%
By what percentage is 208.9 smaller than 225?
Answer: By ≈ 7.16%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).